1. Field of the Invention
The instant disclosure relates generally to an integrated optical module adaptable in a finger sensing device, and pertains particularly to an integrated optical module adaptable in a fingerprint imaging device for finger navigation and biometric scanning purposes.
2. Description of Related Art
While modern devices share a common design trend toward miniaturization in physical size, their functionality has grown tremendously sophisticated and diversified. As a result, conventional human interface devices (HID), such as mouse and keyboard, are often rendered inadequate when adapted . Constant efforts have been devoted to finding a precise and intuitive miniaturized control interface capable of enabling intimate human-machine interaction. Particularly, as these personalized electronic devices are deeply integrated into modern daily life, they are expected to be operated under a variety of conditions. Therefore, the HID thereof should not only be precise and sensitive but also compact and reliable.
Moreover, Human fingerprint is a unique biometric feature that has been long used for identification purposes. As modern electronics become increasingly personalized, the data/information stored thereon are often invaluable. It is desirable to incorporate on the electronic device a security measure to safeguard the information stored thereon and/or to disable the operation thereof in the event of loss or theft. Therefore, it is desirable to incorporate biometric scanning capabilities into modern electronic devices to regulate access and ensure security.
Optical finger navigation (OFN) technology possesses the above desirable attributes in terms of precision, compactness, and reliability. Furthermore, OFN devices can be configured to perform fingerprint scanning functions suitable for biometric recognition applications. Particularly, an OFN device combines the sensitivity and the reliability of a well-developed optical mouse yet poses far less spatial constraint in physical implementation.
On the other hand, as modern electronic devices become growingly personalized and the data/ information stored therein being increasingly invaluable, it is desirable to incorporate security measures to safeguard the information and/or to restrict/ disable the operation of the device, particularly in the event of loss or theft. Human fingerprint is a unique biometric feature that has been long used for identification purposes. Therefore, it is desirable to incorporate biometric scanning capabilities into modern electronic devices to regulate access and ensure security.
However, OFN devices of conventional design often employ separately arranged illumination optical and imaging optical components around the sensing surface, which occupies precious space. Also, a separated optical arrangement may generate less uniformed illumination output across a wide area of the sensing surface, which may reduce the performance of the OFN device. Moreover, finger navigation and fingerprint recognition operations require optical components of different features. Particularly, for fingerprint recognition operations, it is often desirable to employ optical modules that are configured to match with a linear photo detector array. On the other hand, for finger navigation applications, the adaptation of optical modules configured to match with an area detector array is preferred. Therefore, merely placing separate optical components that are suitable for each individual mode of operation in the same device is inefficient from both a cost effectiveness aspect and a space utilization aspect.
Therefore, it is desirable to have an integrated optical mechanism capable of supporting both finger recognition and finger navigation operations and at the same time adaptable in a low-profile package. Furthermore, it is desirable to have a cost-effective and compact finger sensing unit capable of performing both fingerprint recognition and finger navigation functions for adaptation in small portable electronic devices.